Historic Mortars pp 359-372 | Cite as
Influence of the Mechanical Properties of Lime Mortar on the Strength of Brick Masonry
Abstract
This paper aims at improving the quality of lime mortar masonry by understanding the mechanics of mortars and masonry and their interaction. It investigates how the mortar’s compressive and flexural strengths impact the compressive and bond strength of clay brick masonry bound with calcium lime (CL) and natural hydraulic lime (NHL) mortars. It concludes that the strength of the bond has a greater impact on the compressive strength of masonry than the mortar’s strength. The masonry compressive strength increased proportionally to the strength of the bond up to 6 months. A regression analysis, giving a second order equation with coefficient of determination (R2) of 0.918, demonstrates a strong and predictable relationship between bond strength and masonry compressive strength. It was noted that CL90s mortar masonry reaching a high bond value was stronger than that built with a stronger mortar but displaying a poorer bond. Finally, the mechanics of lime mortars and their masonry are similar. The predominantly elastic behaviour of the mortars of higher hydraulic strength compares well with the elastic and brittle behaviour of their masonry, with either little (NHL2) or non-existent plasticity (NHL3.5 and 5); in contrast, the CL90 mortar and masonry exhibit a plastic behaviour.
Keywords
Compressive Strength Bond Strength Flexural Strength Lime Mortar Mortar StrengthNotes
Acknowledgements
The authors thank Paul McMahon, Architectural Heritage Division, Office of Public Works, for supporting this project. All testing was carried out in the Dept. of Civil Engineering, Trinity College Dublin. The authors thank Chris O’Donovan, Dr. Kevin Ryan and Dave McAuley for their assistance with testing; and The Traditional Lime Company, St Astier/CESA Limes, Clogrenanne Lime Ltd and Kingscourt brick for donating materials.
References
- 1.Boothby, T.E.: Analysis of masonry arches and vaults. Prog. Struct. Eng. Mater. 3, 246–256 (2001)CrossRefGoogle Scholar
- 2.Zucchini, A., Lourenzo, P.B.: Mechanics of masonry in compression: results from a homogeneisation approach. Comput. Struct. 85, 193–204 (2006)CrossRefGoogle Scholar
- 3.Gumeste, K.S., Venkatarama Reddy, B.V.: Strength and elasticity of brick masonry prisms and wallettes under compression. Mater. Struct. 29, 241–253 (2007)CrossRefGoogle Scholar
- 4.Venkatarama Reddy, B.V., Vyas Uday, C.V.: Influence of shear bond strength on compressive strength and stress-strain of masonry. Mater. Struct. 41, 1697–1712 (2008)CrossRefGoogle Scholar
- 5.Kaushik, H.B., Rai, D.C., Jain, S.K.: Stress-strain characteristics of clay brick masonry under uniaxial compression. J. Mater. Civil Eng. (ASCE) 19(9), 728–739 (2007)CrossRefGoogle Scholar
- 6.Hedstrom, E.G., Tarhini, K.M., Thomas, R.D., et al.: Flexural bond strength of concrete masonry prisms using PC and hydrated lime mortars. Mason. Soc. J. 9(2), 8–23 (1991)Google Scholar
- 7.Portland Cement Association (PCA): Bond strength testing of masonry. Masonry Information, Skokie (1994)Google Scholar
- 8.Venumadhava Rao, K., Venkatarama Reddy, B.V., Jagadish, K.S.: Influence of flexural bond strength on the compressive strength of masonry. In: Proceedings of the National Conference on Civil Engineering Materials and Structures, pp. 103–108. Osmania University, Hyderabad, India (1995)Google Scholar
- 9.Sarangapani, G., Venkatarama Reddy, B.V., Jagadish, K.S.: Brick–mortar bond and masonry compressive strength. J. Mater. Civil Eng. (ASCE) 17(2), 229–237 (2005)CrossRefGoogle Scholar
- 10.Groot, C.J.W.S.: Effects of water on mortar brick bond. PhD thesis, University of Delft, Delft, The Netherlands (1993)Google Scholar
- 11.Pavía, S., Hanley, R.: Flexural bond strength of natural hydraulic lime mortar and clay brick. Mater. Struct. 43(7), 913–922 (2010). doi: 10.1617/s11527-009-9555-2 CrossRefGoogle Scholar
- 12.CEN: Method of testing cement. Determination of strength, EN 196-1 (2005)Google Scholar
- 13.CEN: Building lime. Part 2. Test methods, EN 459-2 (2001)Google Scholar
- 14.Hanley, R., Pavía, S.: A study of the workability of natural hydraulic lime mortars and its influence on strength. Mater. Struct. 41(2), 373–381 (2008). doi: 10.1617/s11527-007-9250-0 CrossRefGoogle Scholar
- 15.CEN: Method of test masonry: determination of compressive strength, EN 1052-1 (1999)Google Scholar
- 16.CEN: Method of test masonry: determination of flexural strength, EN 1052-2 (1999)Google Scholar
- 17.CEN: Method of test masonry: determination of bond strength, EN 1052-5 (2005)Google Scholar